Thanks, I had the idea of making a game that had its own separate mechanics for ‘room locking’ to apply to, though I had a lot of trouble getting things to work quite right. For the final puzzle,
Spoilers
The key being blue instead of red was intentional, so that you could drop it on the trapdoor in the room below and walk back across the same trapdoor with the lock, which was meant to make the top room possible. I overlooked that it could be done without the lock, that's what I get for rushing level design on the last few hours!If you want to know how the lock was meant to help,
Solution spoilers
You were meant to send the laser across the top path from farther away, then use the border of the room as 'cover' to walk south and back north to get around the laser, with the lock preserving the room's state.I’d do more fixing of these issues, but I don’t want to modify the game any more (level design / unnecessary bug-hunting) while the jam’s still recently finished, in case it’d be too against the spirit of the jam, so I’ll probably fix it in a post-jam expansion if I get around to it.